I have a 2003 CL, will 8K D2R's still work with the factory ballasts or do they need to be updated also?

 

They will work just fine.
As long as there 35w you won't need to upgrade your ballast.

 

Just be aware that 8000K bulbs put less useable light on the road than the OEM 4300K bulbs. (4300K is the best at lighting up the road.) As you increase the Kelvin rating you are trading performance for color. And the diminished output is reported to be even worse in rainy conditions.

Some forum members have even been disappointed with just making the move up to 6000K.